The handling of dry materials in a confined space, such as on an offshore rig, has always been problematic. First, the delivery of material, such as cement, barite, bentonite or hydraulic-fracturing materials, is most economically made in their dry form with mixing to occur offshore. Second, space offshore must be used as economically as possible and finally, accuracy, control and continuity of delivery of the amount of the materials both ordered and used is a challenge. Applicant describes its embodiment for use on an offshore drilling rig, although it is not intended to limit this disclosure to such a use.
But using an offshore rig as an example, typically, a supply boat is used to deliver bulk materials to each rig, which then stores the material in large, heavy pressure vessels until used. After all the material has been removed from the rig's storage container and used, more material must be ordered and delivered to again fill these heavy pressure containers. Excess dry bulk material is generally ordered and stored on the rig to prevent running out of material halfway through a job. The present embodiment obviates the need for such bulk pressure storage facilities.
First, because of the rectangular geometric configuration of the atmospheric tanks used to store the material and the low vertical height of the entire system, higher volumes of dry materials may be more easily stored adjacent multiple separate pressure re-loader tanks. This compact and proximate configuration minimizes the wait for material to be delivered into each re-loading tank for use in the drilling process. Moreover, the loading, unloading, measuring and moving of dry bulk material to its final destination can be performed simultaneously and continuously from the parallel vacuum or pressure re-loading tanks, allowing the rapid completion of well servicing. The atmospheric storage tank or tanks supply the dry bulk material to the smaller vacuum re-loading tanks, which are substantially lighter than the high-pressure tanks ordinarily used in this application. The smaller vacuum or pressure re-loading tanks activated by an automated control system more accurately and rapidly allow the loading and unloading of the dry bulk material, thereby permitting more accurate mixing and use of the material on the rig.
The present system allows rapid loading and efficient storage of dry bulk materials in the atmospheric tanks; moving the dry bulk material more quickly from offshore supply boats or other sources. It also permits more accurate processing of the material after offloading onto the rig and minimizes the time and effort of rig personnel in moving materials on or off the rig and down-hole. Since the system can be closed, materials previously removed from the atmospheric storage tanks and held in the pressure re-loader tanks or in the lines can be redirected back into the storage tanks and the pressurized air running through the re-loader tanks and the lines automatically clears all debris from the system. This entire system is dust-free and low profile allowing this unit to be placed anywhere on a rig floor with available space without risk of dust contamination or injury to rig personnel. Since the atmospheric storage tank walls are thinner, the tank battery on the rig floor is lighter and more compact. Finally, the atmospheric tanks do not require periodic inspection and recertification since they are not maintaining materials under pressure. The present invention's lightweight, compact size, precision and ease of use solve many existing issues for the handling of dry bulk materials in this environment.